Portable coordinate measuring device

Abstract

A coordinate measuring device ( 10 ) comprises a housing ( 12 ) rotatively supported on a base ( 11 ) and mounting a vertical pillar ( 13 ) along which rides a carriage ( 14 ) engaged by a horizontally translating arm ( 15 ). A turret ( 18, 19 ) at each end of the aim houses a rotating body ( 20, 21 ) connected to a probe ( 22, 23 ). The rotation of the base, the vertical movement of the carriage, the horizontal movement of the arm and the rotation of the probes are driven by motors ( 27, 28, 29, 30 ) in the housing. The rotation of the motors are transmitted by a cable and pulley assembly to the arm and carriage. The cable ( 43 ) controlling the transversal movement of the arm has its opposite ends attached to the opposite extremity ( 16, 17 ) of the arm, and is run respectively up and down the portion of the pillar above and below the carriage in order to maintain constant lengths and tension of the cables as the carriage moves up and down the pillar. The rotation of the probes and that of the base are coordinated to keep the probes at a constant angle in relation to the measured surface.

1. A coordinate measuring device which comprises:
 a stationary base; 
 a housing movably supported on said base; 
 
       a pillar mounted on said housing and extending along a first axis;
 a carriage translatable along, and supported by said pillar; 
 a cross-arm slidingly engaged upon said carriage, translatable about a second axis and having a first extremity; 
 an electro-mechanical assembly in said housing, said assembly including a plurality of drives and linkages linking said drives to said translatable carriage and sliding cross-arm. 
 
     
     
       2. The device of  claim 1 , wherein said assembly comprises:
 a plurality of motors, each of said motors having a driving pulley; 
 a plurality of direction-altering pulleys associated with said pillar and carriage; and flexible, elongated elements engaging said pulleys to translate said carriage up and down said pillar and bilaterally translate said arm about said carriage. 
 
     
     
       3. The device of  claim 2 , wherein assembly further comprises a motorized mechanism for rotating said housing and pillar about said first axis. 
     
     
       4. The device of  claim 2 , wherein said device further comprises at least one probe mounted at said first extremity; and, 
       wherein said probe comprises a sensing element. 
     
     
       5. The device of  claim 4 , 
       wherein said sensing element comprises an imaging apparatus. 
     
     
       6. The device of  claim 1 , which further comprises encoders for indicating the linear position of said carriage along said first axis, the linear position of said arm along said second axis, and the position of said housing in relation to said base. 
     
     
       7. The device of  claim 4 , which further comprises:
 a turret secured to said first extremity; 
 a body within said turret, said body being rotatable about a third axis; and 
 wherein said sensing element comprises a shaft coupled at a first end to said body and a sensor mounted at an opposite end. 
 
     
     
       8. The device of  claim 7 , wherein said shaft projects in a direction parallel to and spaced apart from said third axis. 
     
     
       9. The device of  claim 6  which further comprises a control unit activating said drives and automatedly positioning said first extremity in space. 
     
     
       10. The device of  claim 7 , wherein said sensor comprises an imaging apparatus; and said device further comprises a control unit activating said motors and positioning said imaging apparatus proximate a point on a workpiece surface. 
     
     
       11. The device of  claim 4 , which further comprises a second probe secured to a second extremity of said arm. 
     
     
       12. The device of  claim 9 , which further comprises at least one probe; wherein said control unit activates said drives and automatically positions said probe in contact with at least one point on a workpiece surface. 
     
     
       13. The device of  claim 12 , wherein said control unit is adapted to coordinate said linear positions and said position of said housing. 
     
     
       14. The device of  claim 7 , which further comprises a control unit activating said drives; and wherein said control unit is further adapted to adjust an angular position of said shaft in relation to a workpiece surface. 
     
     
       15. The device of  claim 12 , wherein said said control unit is further adapted to run said probe along a path on said surface. 
     
     
       16. The device of  claim 12 , wherein said said control unit is further adapted to intermittently position said probe on a series of discrete points on said surface. 
     
     
       17. The device of  claim 14 , wherein said control unit is further adapted to alternately and bidirectionally rotate said body over an arc of less than 180 degrees. 
     
     
       18. The device of  claim 2 , wherein said elongated elements comprise cables made of synthetic plastic material. 
     
     
       19. The device of  claim 6 , wherein said encoders comprise:
 linear and circular indexers and optical detectors. 
 
     
     
       20. The device of  claim 2 , wherein a first of said flexible elongated elements comprises a cable secured at both ends to said carriage and engaging a first direction-altering pulley in an upper region of said pillar, a second direction-altering pulley in a lower region of said pillar and one of said direction-altering pulleys being driven by a first of said motors. 
     
     
       21. The device of  claim 2 , where said cross-arm further comprises a second extremity opposite said first extremity; and wherein a second of said flexible elongated elements comprises a cable secured at opposite ends to said first and second extremities respectively, running up and down portions of said pillar above and below said carriage, and engaging a pulley driven by a second of said motors. 
     
     
       22. The device of  claim 7 , wherein said device further comprises:
 a cable and pulley mechanism linking said body to one of said motors, and wherein said mechanism comprises a close-loop cable running up and down portions of said pillar above and below said carriage. 
 
     
     
       23. A coordinate measuring device which comprises: 
       a housing; 
       a pillar mounted on said housing and extending along a first axis;
 a carriage translatable along, and supported by said pillar; 
 a cross-arm slidingly engaged upon said carriage, translatable about a second axis and having opposite first and second extremities; 
 an electro-mechanical assembly in said housing, said assembly including a plurality of drives and linkages linking said drives to said translatable carriage and sliding cross-arm; 
 
       wherein said linkages comprise:
   a plurality of direction-altering pulleys associated with said pillar and carriage; and   flexible, elongated elements engaging said pulleys to translate said carriage up and down said pillar and bilaterally translate said arm about said carriage;   wherein a second of said flexible elongated elements comprises a cable secured at opposite ends to said first and second extremities respectively, running up and down portions of said pillar above and below said carriage.   
 
     
     
       24. The device of  claim 23 , wherein said second of said flexible elongated elements engages a pulley driven by at least one of said drives. 
     
     
       25. The device of  claim 23 , which further comprises at least one probe mounted at said first extremity. 
     
     
       26. The device of  claim 23 , wherein said carriage translates along said pillar while said cross-arm remains fixed with respect to said carriage.